Moving watercraft in shallow waterways such as ponds, lagoons and streams can be carried out in different manners. For example, boats have used paddlewheels, inboard or outboard engines coupled to screws, oars, paddles, or even poles to propel the craft along the water. A more challenging problem is presented when the watercraft is a dredge that includes a cutterhead to excavate the bottom of the waterway. The need to dig into the waterway bottom with the cutterhead and the output forces on discharge hoses extending from the dredge can be significant, thus, making the proposition of stabilizing the watercraft by the above-listed propulsion examples difficult. Environmental effects, such as strong winds, can also be a factor in trying to maintain the position and stability of the watercraft.
Another problem is presented when harvesting aquatic weeds such as water hyacinths. The tenacious nature of the weeds and the presences of large root masses with laterally extending roots complicates the problem of positioning and propelling watercraft that use screw drives.
One solution previously employed in positioning dredges or weed harvesting equipment involves the use of winches connected by cable to the shore. By the use of multiple cables connected to the shore, the watercraft can be held in position. Unfortunately, this solution requires that the waterway be small or narrow, and involves considerable labor to erect and maintain the cable system during dredging or harvesting.
There has, thus, evolved a need for a new and improved dredge propulsion system which can be mounted on the watercraft and which avoids the need for connection to the shore. There is further a need for a system for propelling watercraft in shallow water situations which will maintain the position of a dredge or weed harvester despite forces that result from dredging operation or from the environment. Additionally, there is needed a watercraft propulsion system which provides precise positioning in shallow water but is also capable of propelling and maneuvering the watercraft quickly in waterways of any depth. Finally, there is needed a watercraft propulsion system that provides protection and durability of it components when operating on various types of waterways, such as waterways that include cement bottoms.